Chemistry Seminar with Dr. Michael Walter from the University of North Carolina at 4:00pm

Abstract: Thiazolo[5,4-d]thiazoles (TTzs) are attractive materials for a variety of photochemical
and electrochemical applications due to their simple syntheses, strong fluorescence,
and high chemical stability. The unique fused, bicyclic TTz molecular structure enables
multifunctional properties, high-performance fluorescence sensing, anolyte materials
for redox-flow batteries, and as efficient photocatalysts. Dipyridinium, extendedviologen
TTz derivatives exhibit high fluorescent quantum yields (> 90%) and reversible
electrochromic properties. Simple TTz chromogenic hydrogel devices display
electrochromism, electrofluorochromism, and photochromism and exhibit excellent
reversibility and stable fluorescence cycling. We have also shown the ability of alkylated
dipyridinium TTzs to drive the formal addition of potassium organotrifluoroborates
(alkyl-BF3K) to imines with good efficiencies (isolated yields ~ 80-90%) and turnover
numbers (TON, 400-700), using surprisingly low mol% (0.05-0.1) photocatalyst. Newly
designed, asymmetrically substituted, push-pull TTz materials show strong
solvatofluorochromism and are being evaluated as voltage-sensitive dyes for cell
membrane potential sensing. Asymmetric TTzs can be used as a cell membrane VSD and
have shown good cell membrane localization, insignificant cytotoxicity, and
photostabilities that are 4 times higher than comparable dyes. Presented is the recent
work covering these high-performance applications and current studies of TTz
chromophores for efficient for solid-state fluorescence sensing, photoinduced electron
transfer, photochromism, and related solar applications.

Hosted by Prof Bryce Sadtler